1. Field of the Invention
This invention relates to methods and systems for laser processing targets of different types on a workpiece.
2. Background Art
Laser trimming has been a part of manufacturing processes in the semiconductor and microelectronics industries for more than 30 years. The industry has been introducing new link materials and structures, as well as different thin films and structures. One of the challenges for laser processing is to meet the needs to process all these devices with a single laser trimming system. For example, the processing conditions and the types of lasers needed for copper processing are not the same for processing conventional polysilicon links. So a laser trimming system designed for processing polysilicon links may not be able to process copper links effectively.
Another challenge is that the processing conditions and the types of lasers needed for metal link blowing or cutting may not be the best for the conventional thin film trimming. For example, a laser trimming system designed for processing copper links may not be able to process and trim thin film resistors effectively. In addition, different thin films require different processing conditions as well. In a laser processing system such as the model M310 product of the assignee of the present application, various thin film trimming jobs require different laser pulse widths, for example 7 ns and 50 ns pulse widths. Current M310/M350 systems of the assignee of this application are built with a selected laser having a single desired pulse width. However, the pulse width cannot be tuned or adjusted easily. This limits the system to a narrow range of product processing at the selected pulse width. Currently, when there are different types of targets or circuit elements to be laser processed with different laser pulse widths, multiple processing systems provide the needed different pulse width lasers. These systems may be underutilized depending on a mix of products with varying target types, thus reducing system value to the customer. A system for processing multiple types of devices with a single laser source therefore will add value to the customer.
Except where indicated, the following patents and patent applications are assigned to the assignee of the present invention and are hereby incorporated by reference in their entirety:
U.S. Pat. No. 5,300,756 (the '756 patent) entitled “Method For Severing Integrated-Circuit Connection Paths By A Phase-Plate-Adjusted Laser Beam.”
U.S. Pat. No. 5,998,759 (the '759 patent) entitled “Laser Processing.”
U.S. Pat. No. 6,727,458 (the '458 patent) entitled “Energy-Efficient, Laser-Based Method And System For Processing Target Material.”
U.S. Pat. No. 6,777,645 (the '645 patent) entitled “High-Speed, Precision, Laser-Based Method And System For Processing Material Of One Or More Targets Within A Field.”
U.S. Pat. No. 6,951,995 (the '995 patent) entitled “Method And System For High-Speed, Precise Micromachining An Array Of Devices.”
U.S. Pat. No. 6,987,786 (the '786 patent) entitled “Controlling Laser Polarization.”
Published U.S. Patent Publication No. 2002/0167581 (the '7581 publication) entitled “Methods And Systems For Thermal-Based Laser Processing.”
Published U.S. Patent Publication No. 2006/0108337 (the '8337 publication) entitled “Method And System For Laser Soft Marking.”
Published U.S. Patent Publication No. 2004/0188399 (the '8399 publication) entitled “Energy-Efficient, Laser-Based Method And System For Processing Target Material.”
U.S. Pat. No. 6,151,338 (not assigned to the assignee of the present invention) discloses a high power laser optical amplifier system for material processing.